1. How does the potential energy of a valence electron in a Sodium (Na) atom compare to one in Cesium (Cs). Why would elements of the same group have valence electrons with different potential energies (mention at least two physical components of the atom that would contribute to this difference)?
2. If you placed Rb+ and Li+ between two plates, one negative and one positive, they would accelerate toward the negative plate at different rates. Which one would be accelerated faster? Give two reasons for this difference.
3. Explain the terms ‘effective charge (Zeff)’ and ‘effective potential energy (Veff). Why do we create these terms? Write down the general formula for Veff?
4. Draw the effective potential energy diagram for Sodium (Z=11) showing the energy lines for its first (outer most) electron in all three of its electron shells. Label each line with its effective charge.
5. Using the diagram drawn for #4, explain how these different lines determine the binding energy between the nucleus and electron.
6. Describe the general trends in atomic size vs. position in the periodic table.
7. Account for the general trend in atomic size vs. horizontal position in the periodic table.
8. Account for the general trend in atomic size vs. vertical position in the periodic table.
9. Define electronegativity and electron affinity.
10. An element with _______ ionization energy and ______ electron affinity is electropositive. Likewise, an element with _______ ionization energy and _______ electron affinity is electronegative. Name two elements for each case.
11. Arrange the members of each of the following sets of elements in order of increasing electron affinities: (a) Li, K (b) P, S (c) S, Cl (d) Na, Mg (e) Cl, Ar
12. True and false (answer and explain your reasoning)?
1. If energy is released when an atom receives an electron the electron affinity is positive.
2. Electronegativity and electron affinity follow the same exact periodic trends.
3. Even if an isolated gaseous atom needs to gain two electrons in order to resemble the electron configuration of a noble gas (ie. Oxygen) it is still favorable for it to gain that second electron.
4. P and Ca2+ contain the same number of sub-shells
13. With a square as the periodic table indicate with arrows the trends of electronegativity, ionization energy, electron affinity and atomic radius.
14. Can we think about the trends in EN based on the shell structure of the atom? If so, how?
15. As you move from left to right across the 2nd period each element is increasingly more stable. Explain this trend based on ionization energy and electron affinity.
16. Explain why the electrostatic interaction between the valence electrons and the nuclei increases for each element going from left to right across a period. Connect your answer for this question to #15.
17. Why does the EN decrease going down a group?
18. In H2 how many attractive and repulsive interactions are there? Draw a diagram labeling each interaction.
19. Create the potential energy curve, Veff, for two hydrogen atoms coming together. Consider the two atoms to be initially separated by a large distance.
20. On the above graph mark the point where the bond H2 forms. Explain the behavior of the two particles on either side of this point.
21. On the same graph mark the point where the attractive interaction exactly equals the repulsive interaction.
22. What are the two most important quantities on this diagram? Label them.